[C25][DTS] set dummy regulator to backlight, pcie and usb_phy nodes

This is done to get rid of the following warnings in dmesg:
pwm-backlight lvds_backlight@0: supply power not found, using dummy regulator
imx8mq-usb-phy 381f0040.usb-phy: supply vbus not found, using dummy regulator
imx8mq-usb-phy 382f0040.usb-phy: supply vbus not found, using dummy regulator
pwm-backlight lvds_backlight@0: supply power not found, using dummy regulator
imx6q-pcie 33800000.pcie: supply epdev_on not found, using dummy regulator
imx6q-pcie 33c00000.pcie: supply epdev_on not found, using dummy regulator

Signed-off-by: Mikhail Vanyulin <mikhail.vanyulin@rtsoft.de>

arch/arm64/boot/dts/seco/seco-imx8mq-c25.dts

@@ -182,12 +182,20 @@
 		};
 
 		reg_1p8v: regulator-1p8v {
-				compatible = "regulator-fixed";
+			compatible = "regulator-fixed";
 			regulator-name = "1P8V";
 			regulator-min-microvolt = <1800000>;
 			regulator-max-microvolt = <1800000>;
 			regulator-always-on;
 		};
+
+		reg_3v3: regulator-3v3 {
+			compatible = "regulator-fixed";
+			regulator-name = "3V3";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			regulator-always-on;
+		};
 	};
 
 	modem_reset: modem-reset {
@@ -221,6 +229,7 @@
 				     90 91 92 93 94 95 96 97 98 99
 				    100>;
 		default-brightness-level = <80>;
+		power-supply = <&reg_3v3>;
 	};
 
 	panel_edp: edp_panel {
@@ -1000,6 +1009,7 @@
 				 <&clk IMX8MQ_SYS2_PLL_100M>,
 				 <&clk IMX8MQ_SYS2_PLL_250M>;
 	ext_osc = <1>;
+	epdev_on-supply = <&reg_3v3>;
 
 /*
  * On SECO Q7 Dev Kit 2.0 carrier board, a PCIE_RST# signal on Q7 connector
@@ -1032,6 +1042,7 @@
 				 <&clk IMX8MQ_SYS2_PLL_100M>,
 				 <&clk IMX8MQ_SYS2_PLL_250M>;
 	ext_osc = <1>;
+	epdev_on-supply = <&reg_3v3>;
 
 /*
  * On SECO Q7 Dev Kit 2.0 carrier board, a PCIE_RST# signal on Q7 connector
@@ -1201,6 +1212,7 @@
  * |__________________________________________________________________________|
  */
 &usb3_phy0 {
+	vbus-supply = <&reg_3v3>;
 	status = "okay";
 };
 
@@ -1211,6 +1223,7 @@
 };
 
 &usb3_phy1 {
+	vbus-supply = <&reg_3v3>;
 	status = "okay";
 };